1. Field of Invention
This invention relates to new polymeric compositions for use in contact and intraocular lenses and other optical devices.
2. Description of the Prior Art
Carboxylic acid containing polymers for contact lenses and other biomedical uses are well known, for instance see U.S. Pat. No. 3,822,089 granted July 2, 1974 to Otto Wichterle. Their major advantage is the enhanced water content of the polymer and higher oxygen permeability. However, these polymers have low mechanical strength. As a result, other polymeric compositions have been suggested. U. S. Pat. No. 3,937,680 granted to de Carle discloses a terpolymer of hydroxyethyl methacrylate, N-vinyl pyrrolidinone and acrylic acid. While water contents of up to 90% can be achieved, the mechanical properties are unsatisfactory. U.S. Pat. No. 3,988,274 granted Oct. 26, 1976 to E. Masuhara et al discloses that the strength of carboxylic acid containing polymers are enhanced by the use of alkyl methacrylates, e.g., n butyl methacrylate. Further, attempts to improve polymers include the addition of another vinyl monomer, vinyl acetate, see U.S. Pat. No. 4,143,017 granted Mar. 6, 1979 to N. Tarumi et al.
Polysiloxane containing polymers for contact lenses and other biomedical uses are also well known, for instance see U.S. Pat. No. 3,808,178 granted Apr. 30, 1974 to N. G. Gaylord. This patent discloses fabricating contact lenses from a copolymer of polysiloxanyl-alkyl acrylic ester and an alkyl acrylic ester. Improvements in these compositions have been developed. Among these are the improvements disclosed in U S. Pat. No. 4,153,641 granted May 8, 1979 to W. G. Deichert et al which discloses contact lenses made from polymers and copolymers comprising poly(organosiloxane) polymers and copolymers formed by polymerizing a poly(organosiloxane) monomer alpha, omega terminally bonded through divalent hydrocarbon groups to polymerized, free radical polymerizably activated, unsaturated groups forming a polymer in a crosslinked network. U.S. Pat. No. 4,208,506 granted June 1980 to W. G. Deichert et al discloses soft contact lenses made from polymers and copolymers comprising polyparaffinsiloxane polymers and copolymers formed by polymerizing a polyparaffinsiloxane monomer alpha, omega terminally bonded through divalent hydrocarbon groups to polymerized, free radical polymerizably activated, unsaturated groups forming a polymer in a crosslinked network. U.S. Pat. No. 4,303,772 granted Dec. 1, 1981 to N. N. Novicky discloses polysiloxanyl alkyl esters of acrylic and methacrylic acids and its copolymerization with alkyl esters of acrylic, methacrylic acids and/or itaconate esters to produce highly permeable contact lens material The copolymer preferably includes a crosslinking agent and hydrophilic monomer. Contact lenses manufactured from the material are easily machined and polished into hard or semi-hard contact lenses having excellent dimensional stability.
Yet, in spite of the foregoing advances further improvement in compositions for contact and intraocular lenses is desired Added patient comfort, greater visual acuity, durability and the like are desired This search is complicated because compounds similar to those employed above are not suitable for contact lenses. For instance, U.S. Pat. No. 3,743,669 granted July 3, 1973 to M. E. D. Hillman et al discloses that 2-(1-hydroxyalkyl)-acrylates and similar polymers have good adhesive properties.
Among the objects of this invention is to provide polymers for contact and intraocular lenses having improved optical properties, gas permeability, physical strength, machinability and biocompatibility.